Numerous devices are driven by hydraulic motors utilizing pressurized oil developed by a relatively low horsepower gasoline engine driven pump. Applicant's copending application Ser. No. 132,636, previously referred to represents such an apparatus as does the apparatus disclosed in U.S. Pat. No. 3,459,109. Such apparatus requires some means for driving an oil pump and this is usually done by a belt and pulley arrangement driven by the gasoline engine drive shaft. Such apparatus also frequently requires some means for cooling the oil used as the hydraulic fluid. This has been found to be true in the case of small gasoline-powered, hydraulically-driven trowels used for smoothing concrete particularly when the trowel is heavily loaded in extremely hot weather. The typical arrangement employed for cooling the hydraulic fluid has required the use of some type of blower or fan with a separate belt and pulley arrangement for driving the blower or fan off the engine shaft and a separate, bulky radiator arrangement.
Prior to applicant's pending patent application Ser. No. 325,277, so far as applicant is aware, there had not been available a compact oil pump drive and oil cooling arrangement adapted for use with hydraulically-driven apparatus powered by a small horsepower gasoline engine. Thus, applicant's pending application Ser. No. 325,277 provided an improved and more compact oil pumping and oil cooling apparatus for use with rotary trowels used for smoothing concrete.
Applicant's present application has gone further and provides improvements to pending application Ser. No. 325,277 and gives an even more compact system in addition to the improvements.